Address review comments with small factoring out of conditional failu…

…re test pattern.

wgpu/tests/buffer_usages.rs

@@ -1,6 +1,6 @@
 //! Tests for buffer usages validation.
 
-use crate::common::{fail, initialize_test, valid, TestParameters};
+use crate::common::{fail_if, initialize_test, TestParameters};
 use wgt::BufferAddress;
 
 const BUFFER_SIZE: BufferAddress = 1234;
@@ -15,28 +15,18 @@ fn buffer_usage() {
 
  initialize_test(parameters, |ctx| {
  for (expect_validation_error, usage) in
- usages
- .iter()
- .flat_map(|&(expect_validation_error, usages)| {
- usages
- .iter()
- .copied()
- .map(move |u| (expect_validation_error, u))
- })
+ usages.iter().flat_map(|&(expect_error, usages)| {
+ usages.iter().copied().map(move |u| (expect_error, u))
+ })
  {
- let create_buffer = || {
+ fail_if(&ctx.device, expect_validation_error, || {
  let _buffer = ctx.device.create_buffer(&wgpu::BufferDescriptor {
  label: None,
  size: BUFFER_SIZE,
  usage,
  mapped_at_creation: false,
  });
- };
- if expect_validation_error {
- fail(&ctx.device, create_buffer);
- } else {
- valid(&ctx.device, create_buffer);
- }
+ });
  }
  });
  }
@@ -71,7 +61,7 @@ fn buffer_usage() {
  ],
  );
  try_create(
- true,
+ true, // enable Features::MAPPABLE_PRIMARY_BUFFERS
  &[
  (false, always_valid),
  (false, needs_mappable_primary_buffers),

wgpu/tests/common/mod.rs

@@ -331,3 +331,13 @@ pub fn valid<T>(device: &wgpu::Device, callback: impl FnOnce() -> T) -> T {
 
  result
 }
+
+// Run some code in an error scope and assert that validation succeeds or fails depending on the
+// provided `should_fail` boolean.
+pub fn fail_if<T>(device: &wgpu::Device, should_fail: bool, callback: impl FnOnce() -> T) -> T {
+ if should_fail {
+ fail(device, callback)
+ } else {
+ valid(device, callback)
+ }
+}